<?php
    $grade = 75;
	if ($grade >= 80) {
		echo "该成绩的等级为优";
	} 
	elseif ($grade >= 70) {
		echo "该成绩的等级为良";
	}
	elseif ($grade >= 60) {
		echo "该成绩的等级为中";
	}
	else  {
		echo "该成绩的等级为差";
?>